In many cases, machine tools for cutting, shaping, grinding, boring or polishing a workpiece, especially a metal workpiece, into a desired shape or contour, require precisely accurate positioning of a moveable element such as the tool member of the machine tool and/or the workpiece being machined. In such cases, the workshop is usually maintained at a constant temperature, for example, by means of an air conditioner, to prevent thermal deformations, such as might result from the thermal expansion and/or contraction of machine tool components. Nevertheless, the body of the machine tool may be wholly or partly affected by heat emitted by other machines installed nearby and/or by variations in outside temperature. Further, the machine tool body itself may have heat emitting parts which cause thermal deformations of other components of the machine tool, which in turn may result in an error in positioning a moveable element.
It is difficult to accurately estimate and correct positioning errors from such causes, especially when the potential exists for the thermal deformation of a plurality of machine tool components, which will typically include such items as a bed, a column, and/or a head, since any cumulative positioning error will depend on the magnitude of thermal deformation of each such component which will, in turn, depend on the size and material of the various components, and the direction of thermal deformation, which may be different for different components.